I took the car in to the Ford Dealership last Friday. They ran a diagnostic on it and said that the Fuel pressure was only running between 8 and 10 pounds of pressure. They put in a fuel pump and filter and called and said it was done. It was running about 55 pounds after the replacement. I got it and before I got home it started surging(chugging) again. I took it back and they ran the computer on it again and this time the oxygen sensor came up as bad but it didn't have a CEL. Today they put in a new oxygen sensor and it's still acting up. The mechanic said it was going from too rich to too lean. It is doing this almost non stop. They were going to call the Ford expert tech and see if they had any ideas. The mechanic said it could be the timing. the car doesn't run bad when the weather is cold but now that it is hot again it chugs almost all the time. Will timing being off cause it to only run bad when the weather is hot and never miss a beat when the weather is cold. The service manager said they wanted to find out what it was because they were baffled by it. He is going to trouble shoot for free because I told him I was a little upset that I had spent 600.00 and it wasn't fixed. The car has 248000 miles on it and it wont be long before it will be just not worth spending any more money on it. Any ideas you guys have that might cause this to be happening will be greatly appreciated. Thanks in advance.
Henry